L-glutamine, as an amino acid which is widely used in medicines, cosmetics, and health foods, has been produced mostly using compound-resistant or compound-sensitive microorganisms. For example, a sulfaguanidine-resistant strain (JP 1978-017675), an azaserine-resistant microorganism (JP 1980-148094), a penicillin-sensitive microorganism (JP 1992-088994), and a tyrosine-glutamic acid (tyr-glu)-resistant strain (JP 1990-186994) have been used for these purposes.
Under these circumstances, during research for development of strains with improved L-glutamine productivity, the present inventors found mutants having resistance to high concentrations of L-glutamine and a method of producing a high yield of L-glutamine by using the mutants, thus completing the present disclosure.